Risk of heat stress involves more than just temperature: recognising individual risk factors
Heat stress is a complex issue when it comes to keeping workers safe, healthy, and productive. Maintaining a safe internal core temperature (and minimising risks of heat stress) at work is affected by three main factors:
- task (the type of work being undertaken),
- environmental (the nature of work environment), and
- individual (the human body’s ability to tolerate heat).
Heat stress management systems, which rely on setting safe/unsafe limits based just on temperature and humidity, won’t take all three factors into account.
Individual factors
The ability to tolerate heat will vary significantly between workers due to individual and pre-disposing factors. Individual factors which should be considered when assessing risk and identifying suitable controls include (but are not limited to):
Image 1: Individual and pre-disposing factors (this infographic has been sourced from Resources Safety and Health Queensland)
Providing workers with adequate information and training on the risks associated with heat stress, including the signs and symptoms of illness, what to do if an emergency occurs and the controls to put in place to prevent this form an essential component of the risk management process.
Assessing risk
It’s important to remember that, for many workplaces, the level of risk will change throughout the year and, especially in the hotter months, throughout the workday or shift. This means risk assessments should be undertaken regularly to ensure changes in risk factors are taken into account and properly managed.
As part of your heat stress identification and assessment, you should conduct a walk-through survey of the workplace, and ask your workers about their heat stress issues. Consider the work location's previous history of heat stress issues, including what time of day or year and under what circumstances they occurred.
Using the Workplace Health and Safety Queensland (WHSQ) Heat Stress Calculator
To assist in this process, the Heat Stress (basic) Calculator can be a valuable tool. This online calculator allows for a basic risk assessment of heat stress without the need for direct measurement of environmental conditions. It considers factors such as acclimatisation, work demands, clothing, sun exposure, and air movement to provide an initial qualitative review of potential heat stress situations. This can help identify areas where more detailed assessments or immediate interventions are needed.
Questions to consider during a risk assessment include:
- Can the work be done in a cooler environment (for example, scheduling the work for a cooler part of the day)?
- Can ventilation be improved?
- Have workers been properly trained?
- Are workers properly acclimatised to the work and environment?
- Can hot surfaces be insulated or covered to reduce radiant heat?
- Can shields and barriers be installed to protect workers from heat (for example, portable gazebos to provide shade)?
- Can humidity be reduced?
- Can a cool rest area be provided?
- How intense and prolonged is the work?
- Is cool water provided and easily accessible?
- Are workers wearing multiple layers of clothing and/or personal protective equipment (PPE)?
It’s important to maintain and review your controls regularly to ensure they’re working properly, especially where conditions can change frequently.
Further information
Learn more:
- how to manage exposure
- pre-start checklist
- workhealth and safety eTools
- watch Heat stress management – you’re doing it wrong by Dr Matt Brearley, Occupational heat stress consultant.